Security researchers at Aim Labs have recently uncovered a critical zero-click vulnerability in Microsoft 365 Copilot, dubbed "EchoLeak." This flaw allows attackers to extract sensitive organizational data without any user interaction, posing significant risks to data security and privacy.
EchoLeak exploits fundamental design weaknesses in Retrieval-Augmented Generation (RAG) systems like Microsoft 365 Copilot. These systems integrate with Microsoft Graph to access organizational data, including emails, OneDrive files, SharePoint sites, and Teams conversations. The vulnerability leverages what researchers term an "LLM Scope Violation," where malicious instructions embedded in external emails cause the AI system to access and exfiltrate privileged data. This represents a new category of AI security threats that exploit the inherent difficulty of validating unstructured inputs to large language models.
As AI systems become increasingly integrated into enterprise environments, the importance of robust security measures cannot be overstated. Organizations must remain vigilant and proactive in addressing potential vulnerabilities to safeguard sensitive data and maintain trust in AI-driven tools.
Source: cyberkendra.com EchoLeak - Zero-Click AI Vulnerability Discovered in Microsoft 365 Copilot
EchoLeak exploits fundamental design weaknesses in Retrieval-Augmented Generation (RAG) systems like Microsoft 365 Copilot. These systems integrate with Microsoft Graph to access organizational data, including emails, OneDrive files, SharePoint sites, and Teams conversations. The vulnerability leverages what researchers term an "LLM Scope Violation," where malicious instructions embedded in external emails cause the AI system to access and exfiltrate privileged data. This represents a new category of AI security threats that exploit the inherent difficulty of validating unstructured inputs to large language models.The Attack Mechanism
The attack begins with an attacker sending a specially crafted email to the target. This email contains hidden instructions that manipulate Copilot into performing unintended actions. The process involves several sophisticated techniques:- Prompt Injection: Malicious commands are embedded within the email, tricking Copilot into executing unauthorized actions.
- Automatic Tool Invocation: Copilot is manipulated to autonomously search through emails and documents, retrieving sensitive information without the user's knowledge.
- ASCII Smuggling: Sensitive data is exfiltrated using hidden Unicode characters within hyperlinks, which, when clicked, send the data to attacker-controlled servers.
Microsoft's Response
Upon discovery, Microsoft assigned a critical severity rating to the vulnerability and implemented a complete fix on the service side. The company emphasized that the vulnerability has been "fully mitigated" and requires no customer action. Additionally, Microsoft noted that there's no evidence of any real-world exploitation, indicating that no customers were impacted.Broader Implications
The EchoLeak vulnerability underscores the evolving sophistication of AI-enabled attacks. It highlights the need for organizations to implement advanced threat detection systems capable of analyzing content across multiple communication channels, including email, chat, and collaboration platforms. Continuous employee education on emerging threats and the implementation of strict access controls and data loss prevention measures are crucial in mitigating the risks posed by these innovative attack vectors.As AI systems become increasingly integrated into enterprise environments, the importance of robust security measures cannot be overstated. Organizations must remain vigilant and proactive in addressing potential vulnerabilities to safeguard sensitive data and maintain trust in AI-driven tools.
Source: cyberkendra.com EchoLeak - Zero-Click AI Vulnerability Discovered in Microsoft 365 Copilot